The engine finally came out after unclamping half a dozen hoses and figuring out where all the mounting bolts were. Hardest to remove was the one securing the left-side frame slider. The head was stripped and the shaft oxidized but Amir, our experienced instructor taught us a nice trick to bang some shape into the hex for solid enough traction to get it out. 
Next was checking valve clearances using feeler gauges. To get your readings each cylinder needs to be rotated to top dead center (TDC). All were within spec but if any are off the mark the corresponding shims must be replaced.
Ultimately we are looking into the source of an engine knock. Apparently it’s a loose rod bearing connected to the crank shaft. We’ll have a look at that next week. Until then I’m probably going to watch a few Youtube videos on this topic.
